Question

A long solenoid is formed by winding $70$ turns $cm ^{-1}$. If $2.0$ A current flows, then the magnetic field produced inside the solenoid is ______$\left(\mu_o=4 \pi \times 10^{-7} TmA ^{-1}\right)$

• A. $88 \times 10^{-4} T$
• B. $1232 \times 10^{-4} T$
• C. $352 \times 10^{-4} T$
• D. $176 \times 10^{-4} T$

Answer 1

Answer: (D)

$ B =\mu_0 nI $
$ =4 \pi \times 10^{-7} \times 70 \times 10^2 \times 2$
$ =56 \pi \times 10^{-4} T $
$ =176 \times 10^{-4} T$